You can only get them at selected locations which are mentioned below in the article.

LOCATION

Andromada

You can find planes at one and only one location in the whole GTA San Andreas. And that is inside a hangar (a place for storing it) of Las Venturas Airport in the area of Las Venturas. The bad thing is that it can't be found all the time inside the airport. It depends on your LUCK! Good Luck when you visit the airport for it!!!

More Details:

2 types of them are there. Name of first type is 'AT 400' and second is 'Andromada'. AT 400 is bigger in size when compared to Andromada. Also, you can see Andromada but cannot use it throughout the game. One at Las Venturas airport is actually AT-400 which you can drive and control!

=>Some Other Info:-

AT 400

It can't be stored inside your garage of any saving house or safe houses because of its large size.

"Airplane" is in US and Canadian English whereas "Aeroplane" is in British English. Anyways! We're not concerned with spelling! I'll be using both the spellings. :)

You can see one during the 'Stowaway' mission. It involves planting explosives inside the it.

They have very high speeds as compared to all the vehicles! You will know when you drive it! Try it!

There is no cheat on any platform like PC, PS2 or Xbox or Xbox 360 for GTA game !